public void TestScrollToNeighborElement(bool virtualizeItems)
{
var stackSize = new Vector3(100, 200, 300);
var childSize1 = new Vector3(50, 150, 250);
var childSize2 = new Vector3(150, 250, 350);
var childSize3 = new Vector3(250, 250, 350);
var stackPanel = new StackPanel { Size = stackSize, ItemVirtualizationEnabled = virtualizeItems, Orientation = Orientation.Horizontal };
var child1 = new StackPanel { Size = childSize1 };
var child2 = new StackPanel { Size = childSize2 };
var child3 = new StackPanel { Size = childSize3 };
stackPanel.Children.Add(child1);
stackPanel.Children.Add(child2);
stackPanel.Children.Add(child3);
stackPanel.Arrange(Vector3.Zero, false);
// pre-arranged
stackPanel.ScrollToNextLine(Orientation.Horizontal);
Assert.AreEqual(1, stackPanel.ScrollPosition);
stackPanel.ScrollToPreviousLine(Orientation.Horizontal);
Assert.AreEqual(0, stackPanel.ScrollPosition);
stackPanel.ScrolllToElement(1.6f);
stackPanel.ScrollToPreviousLine(Orientation.Horizontal);
Assert.AreEqual(1, stackPanel.ScrollPosition);
stackPanel.ScrolllToElement(1.6f);
stackPanel.ScrollToNextLine(Orientation.Horizontal);
Assert.AreEqual(2, stackPanel.ScrollPosition);
// reset scrolling
stackPanel.ScrollToBeginning(Orientation.Horizontal);
stackPanel.Arrange(Vector3.Zero, false);
// post arranged
stackPanel.InvalidateArrange();
stackPanel.ScrollToNextLine(Orientation.Horizontal);
Assert.AreEqual(0, stackPanel.ScrollPosition);
stackPanel.Arrange(Vector3.Zero, false);
Assert.AreEqual(1, stackPanel.ScrollPosition);
stackPanel.InvalidateArrange();
stackPanel.ScrollToPreviousLine(Orientation.Horizontal);
Assert.AreEqual(1, stackPanel.ScrollPosition);
stackPanel.Arrange(Vector3.Zero, false);
Assert.AreEqual(0, stackPanel.ScrollPosition);
stackPanel.ScrolllToElement(1.6f);
stackPanel.Arrange(Vector3.Zero, false);
stackPanel.InvalidateArrange();
stackPanel.ScrollToPreviousLine(Orientation.Horizontal);
Assert.AreEqual(1.6f, stackPanel.ScrollPosition);
stackPanel.Arrange(Vector3.Zero, false);
Assert.AreEqual(1, stackPanel.ScrollPosition);
stackPanel.ScrolllToElement(1.6f);
stackPanel.Arrange(Vector3.Zero, false);
stackPanel.InvalidateArrange();
stackPanel.ScrollToNextLine(Orientation.Horizontal);
Assert.AreEqual(1.6f, stackPanel.ScrollPosition);
stackPanel.Arrange(Vector3.Zero, false);
Assert.AreEqual(2, stackPanel.ScrollPosition);
}